An Indian summer that recorded a heatwave at Halloween has left retailers with large unsold stocks of winter fashion goods, the British Retail Consortium said on Tuesday.

The BRC said consumers could look forward to deep discounts this autumn unless the weather turned cold in November.

In its monthly check on the state of spending in stores and online, the industry trade body said sales in October were 1.4% higher than in the same month a year earlier, but remained unchanged once increases in floor space were taken into account.

The BRC’s retail sales monitor, conducted with KPMG, found more shopping taking place online, with internet business accounting for more than 18% of non-food sales - the highest proportion since Christmas last year.look forward to propsect of deep discounts unless winter comes soon, says

David McCorquodale, head of retail, KPMG, said: “Looking at these figures, most retailers will feel they were tricked rather than treated in October. Even the most experienced of shopkeepers could not have foreseen a heatwave at Halloween and most were left with sales which were flat at best.

“Sadly, this warmer weather has left many fashion retailers with a substantial stock overhang, raising the question of earlier and deeper discounts as we get closer to Christmas. Retailers need a nippy November to help them sell their winter stock before the season’s out.”

Helen Dickinson, director general, British Retail Consortium, said: “Online sales took their largest slice of the pie of non-food sales growth since December 2013. October’s growth compared to last year was 3.3 percentage points faster, which bodes well for Christmas, especially as the proportion of online non-food sales was also the highest recorded since last Christmas.

“October saw many actions to encourage the sale of winter stock. Concurrent flash sales were run in-store and online. Loyal customers were offered exclusive discounts and due to this Clothing and Footwear did better online than in stores.”